Ashton I K, Francis M J
J Endocrinol. 1977 Aug;74(2):205-12. doi: 10.1677/joe.0.0740205.
The incorporation of [3H]thymidine by rabbit chondrocytes in vitro has been developed as a sensitive assay for plasma somatomedin. A concentration of normal plasma of 2-5% enhanced [3H]thymidine incorporation by 5- to 20-fold compared with basal levels in the absence of plasma. The mean potency of plasma from normal adult men was 0-96+/-0-1 u./ml (mean+/-S.D.) and from acromegalic patients 1-9+/-0-4 u./ml. The apparent potency of hypopituitary plasma alone increased on heating which suggested the presence of heat-labile inhibitors of somatomedin activity. The potency of heated hypopituitary plasma (0-6+/-0-09 u./ml) remained significantly lower (P less than 0-01) than normal plasma. Human growth hormone (0-1-20 muu./ml), bovine growth hormone (0-5 20 muu./ml), insulin (0-5-5 muu./ml) and glucose (0-3-2 mmol/1) had no direct effect on the incorporation of [3H]thymidine. Chondrocytes which had been previously stored frozen also showed a response to plasma somatomedin.
兔软骨细胞在体外掺入[3H]胸腺嘧啶核苷已被开发成为一种检测血浆生长调节素的灵敏方法。与无血浆时的基础水平相比，2%-5%的正常血浆浓度可使[3H]胸腺嘧啶核苷的掺入量增加5至20倍。正常成年男性血浆的平均效价为0.96±0.1单位/毫升（平均值±标准差），肢端肥大症患者血浆的平均效价为1.9±0.4单位/毫升。单独的垂体功能减退症患者血浆在加热后其表观效价增加，这表明存在生长调节素活性的热不稳定抑制剂。加热后的垂体功能减退症患者血浆（0.6±0.09单位/毫升）仍显著低于正常血浆（P<0.01）。人生长激素（0.1-20毫微克/毫升）、牛生长激素（0.5-20毫微克/毫升）、胰岛素（0.5-5毫微克/毫升）和葡萄糖（0.3-2毫摩尔/升）对[3H]胸腺嘧啶核苷的掺入没有直接影响。先前冷冻保存的软骨细胞对血浆生长调节素也有反应。
